Coaxial transmission mediums for conveying information at microwave frequencies are often particularly characterized by their relatively small size which is not only a consequence of the operation frequency range, but is also particularly attributable to the applications and environments of the systems in which they are employed. For example, such systems may be found in sophisticated aircraft in which the size and weight of microwave electronics systems must be established as small and light to the extent reasonably possible.
In one specialized configuration for coupling together two such mediums (such as by coupling adjacent modules), the inner conductor mating element of each medium is configured as a male, and a double-ended female component (sometimes termed a "bullet") receives both male elements to complete the center conductor connection at the junction. Each female center conductor element of the bullet is typically provided with at least a pair of diametrically opposed longitudinal slots to effect a spring bias (particularly when opposing sides of the element are normally slightly sprung toward one another) for grasping the male center conductor elements of the adjoining modules.
An insidious problem which has been found to be associated with connections effected by such a connector system, when employed at microwave frequencies, is an erratic increase in the standing wave ratio (SWR) and insertion loss which can account for a significant signal loss/degradation. It has been found that a prominent source of such signal degradation is due to slight axial misalignment of the facing coupled male center conductor elements which cause the bullet, and each of its female center conductor elements, to be substantially skewed from longitudinal alignment with either of the male center conductor elements. Those skilled in the art will understand that the axial misalignment between the facing male center conductor elements may be either such that their respective axes may be parallel or non-parallel to one another. As a result of this axial misalignment, the two contact points between each of the male and female center conductor element pairs have been shown to be substantially longitudinally misplaced from diametric opposition, the latter being the ideal orientation for minimizing reflection and attenuation (or loss) at the joint. Further investigation has shown that this problem, associated with the skewing of the bullet from longitudinal alignment with the longitudinal axes of the facing male center conductor elements of modules or the like is a consequence of employing the standard configuration for the female center conductor element walls and is inevitable so long as the standard, more or less cylindrical, interior surface is utilized.
It is to minimizing reflection and attenuation from connector joints between mating coaxial transmission mediums that this invention is directed.